Malignant rhabdoid tumor of the parapharyngeal space

Malignant rhabdoid tumor has been a somewhat controversial entity since it was first described in 1978 as a possible sarcomatous variant of Wilms tumor. Eventually, however, it was found to be a distinct neoplastic tumor with histologic characteristics similar to those of rhabdomyosarcoma. Malignant rhabdoid tumors affect children. Clinically, they occur primarily in the kidney, and they behave aggressively. Associated mortality is significant, even with combined-modality treatment regimens. We describe the case of a large extrarenal malignant rhabdoid tumor of the parapharyngeal space with extension to the infratemporal fossa and skull base in a previously healthy 2-year-old girl who had presented with a cervical mass and ipsilateral Horner syndrome. The patient underwent complete surgical extirpation of the lesion and received adjunctive cisplatin chemotherapy and radiation therapy, and she remained disease-free at 9 months of follow-up. Given the age group of the patients that these neoplasms most commonly affect and given the neoplasms' resemblance to rhabdomyosarcoma and other small round-cell tumors of the head and neck, discussion of the associated clinical pathology, imaging characteristics, histopathologic features, and mode of management are of particular importance, especially so in view of the uncommon location of the tumor in this specific case. Such a discussion may help lead to minimization of misdiagnosis and maximization of therapeutic benefit.